Determine the polarization properties of Earth-observation satellites

Determine the polarization properties, including the Stokes parameters, of the Earth-observation satellites used as beam probes by the Canadian Galactic Emission Mapper, in order to enable direct satellite-based beam measurements rather than validation of an existing beam model.

Background

The Canadian Galactic Emission Mapper observes Earth-observation satellites emitting in its 8–10 GHz frequency band. These satellites are useful beam probes because they are bright, frequently observed, and can trace the telescope beam to approximately 40 dB below its peak. However, direct beam measurements require knowledge of each satellite’s emitted Stokes parameters. Since those polarization properties are currently unknown, the analysis instead fits the satellite Stokes parameters simultaneously with the beam model and therefore serves only as a validation of the existing model. Establishing the satellites’ polarization properties would make it possible to use them as direct, full-angular-resolution beam calibrators.